This invention relates to 24R- and 24S-fluoro analogs of 1.alpha.,25-dihydroxycholecalciferol.
Vitamin D.sub.3 is a well-known agent for the control of calcium and phosphorous homeostasis. In the normal animal or human this compound is known to stimulate intestinal calcium transport and bone-calcium mobilization and is effective in preventing rickets.
It is also now well known that to be effective, vitamin D.sub.3 must be converted in vivo to its hydroxylated forms. For example, the vitamin is first hydroxylated in the liver to form 25-hydroxy-vitamin D.sub.3 and is further hydroxylated in the kidney to produce 1.alpha.,25-dihydroxy vitamin D.sub.3 or 24,25-dihydroxy vitamin D.sub.3. The 1.alpha.-hydroxylated form of the vitamin is generally considered to be the physiologically active or hormonal form of the vitamin and to be responsible for what are termed the vitamin D-like activities, such as increasing intestinal absorption of calcium and phosphate, mobilizing bone mineral, and retaining calcium in the kidneys.
Since the discovery of biologically active metabolites of vitamin D there has been much interest in the preparation of structural analogs of these metabolites, because such compounds may represent useful therapeutic agents for the treatment of diseases resulting from calcium metabolism disorders.